Techniques for phase tracking to enable higher modulation orders in wireless communications

ABSTRACT

Aspects described herein relate receiving a signal having a waveform including, within a symbol, resource elements for a physical downlink shared channel (PDSCH) and separate resource elements for multiple pilots to enable phase tracking, estimating, based on the multiple pilots, a channel response of the PDSCH, and removing, from the signal, a phase noise computed based on the channel response estimated for the PDSCH.

CLAIM OF PRIORITY UNDER 35 U.S.C. § 119

The present Application for Patent is a continuation of patentapplication Ser. No. 16/803,648, entitled “TECHNIQUES FOR PHASE TRACKINGTO ENABLE HIGHER MODULATION ORDERS IN WIRELESS COMMUNICATIONS” filedFeb. 27, 2020, which is assigned to the assignee hereof and herebyexpressly incorporated by reference herein for all purposes.

BACKGROUND

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to phase tracking.

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems, andorthogonal frequency-division multiple access (OFDMA) systems, andsingle-carrier frequency division multiple access (SC-FDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. For example, a fifth generation (5G)wireless communications technology (which can be referred to as 5G newradio (5G NR)) is envisaged to expand and support diverse usagescenarios and applications with respect to current mobile networkgenerations. In an aspect, 5G communications technology can include:enhanced mobile broadband addressing human-centric use cases for accessto multimedia content, services and data; ultra-reliable-low latencycommunications (URLLC) with certain specifications for latency andreliability; and massive machine type communications, which can allow avery large number of connected devices and transmission of a relativelylow volume of non-delay-sensitive information.

In many wireless communication technologies, communications occurbetween nodes of the network, which may include user equipment (UEs),base stations (e.g., gNBs), etc., using modulation schemes to modulatedata into signals for transmission over-the-air. In 5G NR, modulationschemes are limited to 256 quadrature amplitude modulation (QAM) due tovarious radio frequency (RF) noise floors.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

According to an example, a method of wireless communication at a userequipment (UE) is provided. The method includes receiving a signalhaving a waveform including, within a symbol, resource elements for aphysical downlink shared channel (PDSCH) and separate resource elementsfor multiple pilots to enable phase tracking, estimating, based on themultiple pilots, a channel response of the PDSCH, and removing, from thesignal, a phase noise computed based on the channel response estimatedfor the PDSCH.

In another example, an apparatus for wireless communication is providedthat includes a transceiver, a memory, and one or more processorscommunicatively coupled with the transceiver and the memory. The one ormore processors are configured to receive a signal having a waveformincluding, within a symbol, resource elements for a PDSCH and separateresource elements for multiple pilots to enable phase tracking,estimate, based on the multiple pilots, a channel response of the PDSCH,and remove, from the signal, a phase noise computed based on the channelresponse estimated for the PDSCH.

In another example, an apparatus for wireless communication is providedthat includes means for receiving a signal having a waveform including,within a symbol, resource elements for a PDSCH and separate resourceelements for multiple pilots to enable phase tracking, means forestimating, based on the multiple pilots, a channel response of thePDSCH, and means for removing, from the signal, a phase noise computedbased on the channel response estimated for the PDSCH.

In another example, a non-transitory computer-readable medium includingcode executable by one or more processors for wireless communications isprovided. The code includes code for receiving a signal having awaveform including, within a symbol, resource elements for a PDSCH andseparate resource elements for multiple pilots to enable phase tracking,estimating, based on the multiple pilots, a channel response of thePDSCH, and removing, from the signal, a phase noise computed based onthe channel response estimated for the PDSCH.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction withthe appended drawings, provided to illustrate and not to limit thedisclosed aspects, wherein like designations denote like elements, andin which:

FIG. 1 illustrates an example of a wireless communication system, inaccordance with various aspects of the present disclosure;

FIG. 2 is a block diagram illustrating an example of a node, inaccordance with various aspects of the present disclosure;

FIG. 3 is a flow chart illustrating an example of a method forgenerating a waveform with multiple pilots, in accordance with variousaspects of the present disclosure;

FIG. 4 illustrates examples of waveform configurations includingresource elements for multiple pilots, in accordance with variousaspects of the present disclosure;

FIG. 5 illustrates an example of a method for canceling phase noise froma waveform in a frequency domain, in accordance with various aspects ofthe present disclosure;

FIG. 6 illustrates an example of a method for canceling phase noise froma waveform in a time domain, in accordance with various aspects of thepresent disclosure; and

FIG. 7 is a block diagram illustrating an example of a MIMOcommunication system including a base station and a UE, in accordancewith various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that such aspect(s) maybe practiced without these specific details.

The described features generally relate to generating signals with pilotpatterns to enable higher modulation schemes in wireless communications.In an example, nodes communicating in a wireless network can transmitsignals with pilot patterns to enable phase noise suppression that canallow for achieving the higher modulation orders. For example, the pilotpattern can include transmitting multiple pilots per signal. In oneexample, the multiple pilots can be interleaved in frequency resourceelements (REs) of the signal. In another example, the multiple pilotscan be in adjacent frequency REs of the signal. In addition, forexample, the multiple pilots can be generated according to a sequence(e.g., a Zadoff-Chu sequence, pseudo-noise (PN) sequence, etc.). In anycase, transmitting a signal with multiple pilots can enable improvedphase noise suppression, which can all for achieving higher modulationorder.

Currently in fifth generation (5G) new radio (NR), modulation schemesare limited to 256 quadrature amplitude modulation (QAM) due to variousradio frequency (RF) noise floors. One of the dominant floors is phasenoise arising from the transmit (Tx) and/or receive (Rx) localoscillators (LOs). Cancellation of this noise floor can enablesignificant increase of modulation order to enable modulation orders upto 16,384 QAM (16K-QAM), 1,048,576 QAM (1M-QAM), etc., which can alsoresult in increased throughput for communications (e.g., going from 8bits per second (bps)/Hertz (Hz) to 14 or even 20 bps/Hz can introduce a75%-150% increase in throughput). For example, signal-to-noise ratio(SNR) with code to achieve 16K-QAM can be ˜42 decibel (dB), and toachieve 1M-QAM can be ˜60 dB. In a specific example, in a first phasenoise model of −96 dBc/Hz @ 100 Kilohertz (KHz), an integrated noisefloor can be ˜35 dBc. In another specific example, in a second phasenoise model of −106 dBc/Hz @ 100 KHz, an integrated noise floor can be−45 dBc. Thus, even with infinite thermal SNR, the net available SNR iscapped to this floor (e.g., 35 dB or 45 dB). Removal of dominant phasenoise floors such as these, as described herein, can help to achievethese higher modulation orders. Using additional pilots can allow forsuppressing phase noise to enable the higher modulation orders.

The described features will be presented in more detail below withreference to FIGS. 1-7 .

As used in this application, the terms “component,” “module,” “system”and the like are intended to include a computer-related entity, such asbut not limited to hardware, firmware, a combination of hardware andsoftware, software, or software in execution. For example, a componentmay be, but is not limited to being, a process running on a processor, aprocessor, an object, an executable, a thread of execution, a program,and/or a computer. By way of illustration, both an application runningon a computing device and the computing device can be a component. Oneor more components can reside within a process and/or thread ofexecution and a component can be localized on one computer and/ordistributed between two or more computers. In addition, these componentscan execute from various computer readable media having various datastructures stored thereon. The components can communicate by way oflocal and/or remote processes such as in accordance with a signal havingone or more data packets, such as data from one component interactingwith another component in a local system, distributed system, and/oracross a network such as the Internet with other systems by way of thesignal.

Techniques described herein may be used for various wirelesscommunication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, andother systems. The terms “system” and “network” may often be usedinterchangeably. A CDMA system may implement a radio technology such asCDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases 0 and Aare commonly referred to as CDMA2000 1×, 1×, etc. IS-856 (TIA-856) iscommonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. ATDMA system may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA system may implement a radiotechnology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA),IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, andGSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies, including cellular (e.g., LTE) communicationsover a shared radio frequency spectrum band. The description below,however, describes an LTE/LTE-A system for purposes of example, and LTEterminology is used in much of the description below, although thetechniques are applicable beyond LTE/LTE-A applications (e.g., to fifthgeneration (5G) new radio (NR) networks or other next generationcommunication systems).

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

Various aspects or features will be presented in terms of systems thatcan include a number of devices, components, modules, and the like. Itis to be understood and appreciated that the various systems can includeadditional devices, components, modules, etc. and/or may not include allof the devices, components, modules etc. discussed in connection withthe figures. A combination of these approaches can also be used.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) can includebase stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and/or a5G Core (5GC) 190. The base stations 102 may include macro cells (highpower cellular base station) and/or small cells (low power cellular basestation). The macro cells can include base stations. The small cells caninclude femtocells, picocells, and microcells. In an example, the basestations 102 may also include gNBs 180, as described further herein. Inone example, some nodes of the wireless communication system may have amodem 240 and communicating component 242 for generating a waveform withmultiple pilots and/or performing phase noise suppression on a receivedwaveform based on multiple pilots, as described herein. In particular, aUE 104 and base station 102/gNB 180 are shown as having the modem 240and communicating component 242. This is one illustrative example, andsubstantially any node or type of node may include a modem 240 andcommunicating component 242 for providing corresponding functionalitiesdescribed herein.

The base stations 102 configured for 4G LTE (which can collectively bereferred to as Evolved Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC160 through backhaul links 132 (e.g., using an S1 interface). The basestations 102 configured for 5G NR (which can collectively be referred toas Next Generation RAN (NG-RAN)) may interface with 5GC 190 throughbackhaul links 184. In addition to other functions, the base stations102 may perform one or more of the following functions: transfer of userdata, radio channel ciphering and deciphering, integrity protection,header compression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160 or 5GC190) with each other over backhaul links 134 (e.g., using an X2interface). The backhaul links 134 may be wired or wireless.

The base stations 102 may wirelessly communicate with one or more UEs104. Each of the base stations 102 may provide communication coveragefor a respective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacro cells may be referred to as a heterogeneous network. Aheterogeneous network may also include Home Evolved Node Bs (eNBs)(HeNBs), which may provide service to a restricted group, which can bereferred to as a closed subscriber group (CSG). The communication links120 between the base stations 102 and the UEs 104 may include uplink(UL) (also referred to as reverse link) transmissions from a UE 104 to abase station 102 and/or downlink (DL) (also referred to as forward link)transmissions from a base station 102 to a UE 104. The communicationlinks 120 may use multiple-input and multiple-output (MIMO) antennatechnology, including spatial multiplexing, beamforming, and/or transmitdiversity. The communication links may be through one or more carriers.The base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10,15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrieraggregation of up to a total of Yx MHz (e.g., for x component carriers)used for transmission in the DL and/or the UL direction. The carriersmay or may not be adjacent to each other. Allocation of carriers may beasymmetric with respect to DL and UL (e.g., more or less carriers may beallocated for DL than for UL). The component carriers may include aprimary component carrier and one or more secondary component carriers.A primary component carrier may be referred to as a primary cell (PCell)and a secondary component carrier may be referred to as a secondary cell(SCell).

In another example, certain UEs 104 may communicate with each otherusing device-to-device (D2D) communication link 158. The D2Dcommunication link 158 may use the DL/UL WWAN spectrum. The D2Dcommunication link 158 may use one or more sidelink channels, such as aphysical sidelink broadcast channel (PSBCH), a physical sidelinkdiscovery channel (PSDCH), a physical sidelink shared channel (PSSCH),and a physical sidelink control channel (PSCCH). D2D communication maybe through a variety of wireless D2D communications systems, such as forexample, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ NR and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102′,employing NR in an unlicensed frequency spectrum, may boost coverage toand/or increase capacity of the access network.

A base station 102, whether a small cell 102′ or a large cell (e.g.,macro base station), may include an eNB, gNodeB (gNB), or other type ofbase station. Some base stations, such as gNB 180 may operate in atraditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies,and/or near mmW frequencies in communication with the UE 104. When thegNB 180 operates in mmW or near mmW frequencies, the gNB 180 may bereferred to as an mmW base station. Extremely high frequency (EHF) ispart of the RF in the electromagnetic spectrum. EHF has a range of 30GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters.Radio waves in the band may be referred to as a millimeter wave. NearmmW may extend down to a frequency of 3 GHz with a wavelength of 100millimeters. The super high frequency (SHF) band extends between 3 GHzand 30 GHz, also referred to as centimeter wave. Communications usingthe mmW/near mmW radio frequency band has extremely high path loss and ashort range. The mmW base station 180 may utilize beamforming 182 withthe UE 104 to compensate for the extremely high path loss and shortrange. A base station 102 referred to herein can include a gNB 180.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMES 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, and/or other IP services. The BM-SC 170 may provide functionsfor MBMS user service provisioning and delivery. The BM-SC 170 may serveas an entry point for content provider MBMS transmission, may be used toauthorize and initiate MBMS Bearer Services within a public land mobilenetwork (PLMN), and may be used to schedule MBMS transmissions. The MBMSGateway 168 may be used to distribute MBMS traffic to the base stations102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN)area broadcasting a particular service, and may be responsible forsession management (start/stop) and for collecting eMBMS relatedcharging information.

The 5GC 190 may include a Access and Mobility Management Function (AMF)192, other AMFs 193, a Session Management Function (SMF) 194, and a UserPlane Function (UPF) 195. The AMF 192 may be in communication with aUnified Data Management (UDM) 196. The AMF 192 can be a control nodethat processes the signaling between the UEs 104 and the 5GC 190.Generally, the AMF 192 can provide QoS flow and session management. UserInternet protocol (IP) packets (e.g., from one or more UEs 104) can betransferred through the UPF 195. The UPF 195 can provide UE IP addressallocation for one or more UEs, as well as other functions. The UPF 195is connected to the IP Services 197. The IP Services 197 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved NodeB (eNB), an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), a transmit reception point(TRP), or some other suitable terminology. The base station 102 providesan access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs104 include a cellular phone, a smart phone, a session initiationprotocol (SIP) phone, a laptop, a personal digital assistant (PDA), asatellite radio, a global positioning system, a multimedia device, avideo device, a digital audio player (e.g., MP3 player), a camera, agame console, a tablet, a smart device, a wearable device, a vehicle, anelectric meter, a gas pump, a large or small kitchen appliance, ahealthcare device, an implant, a sensor/actuator, a display, or anyother similar functioning device. Some of the UEs 104 may be referred toas IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heartmonitor, etc.). IoT UEs may include machine type communication(MTC)/enhanced MTC (eMTC, also referred to as category (CAT)-M, Cat M1)UEs, NB-IoT (also referred to as CAT NB1) UEs, as well as other types ofUEs. In the present disclosure, eMTC and NB-IoT may refer to futuretechnologies that may evolve from or may be based on these technologies.For example, eMTC may include FeMTC (further eMTC), eFeMTC (enhancedfurther eMTC), mMTC (massive MTC), etc., and NB-IoT may include eNB-IoT(enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), etc. The UE 104may also be referred to as a station, a mobile station, a subscriberstation, a mobile unit, a subscriber unit, a wireless unit, a remoteunit, a mobile device, a wireless device, a wireless communicationsdevice, a remote device, a mobile subscriber station, an accessterminal, a mobile terminal, a wireless terminal, a remote terminal, ahandset, a user agent, a mobile client, a client, or some other suitableterminology.

In an example, communicating component 242 of one node (e.g., a basestation 102/gNB 180) can transmit a signal with a waveform havingmultiple pilots to allow for improved phase noise suppression. Acommunicating component 242 of another node (e.g., a UE 104) can receivethe signal and can perform the phase noise suppression based on themultiple pilots, which can allow for achieving a higher modulationorder. Thus, for example, the node transmitting the signal can generatethe signal based on the higher modulation order (e.g., 16K-QAM, 1M-QAM,etc.).

Turning now to FIGS. 2-7 , aspects are depicted with reference to one ormore components and one or more methods that may perform the actions oroperations described herein, where aspects in dashed line may beoptional. Although the operations described below in FIGS. 3, 5, and 6are presented in a particular order and/or as being performed by anexample component, it should be understood that the ordering of theactions and the components performing the actions may be varied,depending on the implementation. Moreover, it should be understood thatthe following actions, functions, and/or described components may beperformed by a specially programmed processor, a processor executingspecially programmed software or computer-readable media, or by anyother combination of a hardware component and/or a software componentcapable of performing the described actions or functions.

Referring to FIG. 2 , one example of an implementation of a node 200,which can include a UE 104, base station 102/gNB 180, and/orsubstantially any node that can perform wireless communications. Thenode 200 may include a variety of components, some of which have alreadybeen described above and are described further herein, includingcomponents such as one or more processors 212 and memory 216 andtransceiver 202 in communication via one or more buses 244, which mayoperate in conjunction with modem 240 and/or communicating component 242for communicating using waveforms having multiple pilots, performingphase noise suppression on signals having such waveforms, etc., asdescribed further herein.

In an aspect, the one or more processors 212 can include a modem 240and/or can be part of the modem 240 that uses one or more modemprocessors. Thus, the various functions related to communicatingcomponent 242 may be included in modem 240 and/or processors 212 and, inan aspect, can be executed by a single processor, while in otheraspects, different ones of the functions may be executed by acombination of two or more different processors. For example, in anaspect, the one or more processors 212 may include any one or anycombination of a modem processor, or a baseband processor, or a digitalsignal processor, or a transmit processor, or a receiver processor, or atransceiver processor associated with transceiver 202. In other aspects,some of the features of the one or more processors 212 and/or modem 240associated with communicating component 242 may be performed bytransceiver 202.

Also, memory 216 may be configured to store data used herein and/orlocal versions of applications 275 or communicating component 242 and/orone or more of its subcomponents being executed by at least oneprocessor 212. Memory 216 can include any type of computer-readablemedium usable by a computer or at least one processor 212, such asrandom access memory (RAM), read only memory (ROM), tapes, magneticdiscs, optical discs, volatile memory, non-volatile memory, and anycombination thereof. In an aspect, for example, memory 216 may be anon-transitory computer-readable storage medium that stores one or morecomputer-executable codes defining communicating component 242 and/orone or more of its subcomponents, and/or data associated therewith, whennode 200 is operating at least one processor 212 to executecommunicating component 242 and/or one or more of its subcomponents.

Transceiver 202 may include at least one receiver 206 and at least onetransmitter 208. Receiver 206 may include hardware, firmware, and/orsoftware code executable by a processor for receiving data, the codecomprising instructions and being stored in a memory (e.g.,computer-readable medium). Receiver 206 may be, for example, a radiofrequency (RF) receiver. In an aspect, receiver 206 may receive signalstransmitted by another node in the wireless network. Additionally,receiver 206 may process such received signals, and also may obtainmeasurements of the signals, such as, but not limited to, Ec/Io,signal-to-noise ratio (SNR), reference signal received power (RSRP),received signal strength indicator (RSSI), etc. Transmitter 208 mayinclude hardware, firmware, and/or software code executable by aprocessor for transmitting data, the code comprising instructions andbeing stored in a memory (e.g., computer-readable medium). A suitableexample of transmitter 208 may including, but is not limited to, an RFtransmitter.

Moreover, in an aspect, node 200 may include RF front end 288, which mayoperate in communication with one or more antennas 265 and transceiver202 for receiving and transmitting radio transmissions, for example,wireless communications transmitted by another node or wirelesstransmissions transmitted by node 200. RF front end 288 may be connectedto one or more antennas 265 and can include one or more low-noiseamplifiers (LNAs) 290, one or more switches 292, one or more poweramplifiers (PAs) 298, and one or more filters 296 for transmitting andreceiving RF signals.

In an aspect, LNA 290 can amplify a received signal at a desired outputlevel. In an aspect, each LNA 290 may have a specified minimum andmaximum gain values. In an aspect, RF front end 288 may use one or moreswitches 292 to select a particular LNA 290 and its specified gain valuebased on a desired gain value for a particular application.

Further, for example, one or more PA(s) 298 may be used by RF front end288 to amplify a signal for an RF output at a desired output powerlevel. In an aspect, each PA 298 may have specified minimum and maximumgain values. In an aspect, RF front end 288 may use one or more switches292 to select a particular PA 298 and its specified gain value based ona desired gain value for a particular application.

Also, for example, one or more filters 296 can be used by RF front end288 to filter a received signal to obtain an input RF signal. Similarly,in an aspect, for example, a respective filter 296 can be used to filteran output from a respective PA 298 to produce an output signal fortransmission. In an aspect, each filter 296 can be connected to aspecific LNA 290 and/or PA 298. In an aspect, RF front end 288 can useone or more switches 292 to select a transmit or receive path using aspecified filter 296, LNA 290, and/or PA 298, based on a configurationas specified by transceiver 202 and/or processor 212.

As such, transceiver 202 may be configured to transmit and receivewireless signals through one or more antennas 265 via RF front end 288.In an aspect, transceiver may be tuned to operate at specifiedfrequencies such that node 200 can communicate with, for example, one ormore other nodes. In an aspect, for example, modem 240 can configuretransceiver 202 to operate at a specified frequency and power levelbased on the configuration of the node 200 and the communicationprotocol used by modem 240.

In an aspect, modem 240 can be a multiband-multimode modem, which canprocess digital data and communicate with transceiver 202 such that thedigital data is sent and received using transceiver 202. In an aspect,modem 240 can be multiband and be configured to support multiplefrequency bands for a specific communications protocol. In an aspect,modem 240 can be multimode and be configured to support multipleoperating networks and communications protocols. In an aspect, modem 240can control one or more components of node 200 (e.g., RF front end 288,transceiver 202) to enable transmission and/or reception of signals fromthe network based on a specified modem configuration. In an aspect, themodem configuration can be based on the mode of the modem and thefrequency band in use. In another aspect, the modem configuration can bebased on configuration information associated with node 200.

In an aspect, communicating component 242 can optionally include awaveform generating component 252 for generating waveforms fortransmitting signals that include multiple pilots, a noise suppressingcomponent 254 for performing phase noise suppression on received signalshaving waveforms with multiple pilots, etc., as described furtherherein.

In an aspect, the processor(s) 212 may correspond to one or more of theprocessors described in connection with the UE or base station in FIG. 7. Similarly, the memory 216 may correspond to the memory described inconnection with the UE or base station in FIG. 7 .

FIG. 3 illustrates a flow chart of an example of a method 300 forgenerating a waveform having multiple pilots. In an example, a basestation 102/gNB 180, UE 104, or other node capable of wirelesscommunications, can perform the functions described in method 300 usingone or more of the components described in FIGS. 1-2 .

In method 300, at Block 302, a waveform including REs for data andseparate REs for multiple pilots in a symbol can be generated. In anaspect, waveform generating component 252, e.g., in conjunction withprocessor(s) 212, memory 216, transceiver 202, communicating component242, etc., can generate the waveform including the REs for data andseparate REs for multiple pilots in the symbol. For example, thewaveform can be generated over a collection of frequency resources in aperiod of time. For example, the collection of frequency resources caninclude multiple subcarriers in a frequency spectrum that can be definedfor communications between devices. In addition, for example, the periodof time can include an orthogonal frequency division multiplexing (OFDM)symbol, single carrier frequency division multiplexing (SC-FDM) symbol,and/or the like. In some wireless communication technologies, such as 5GNR, an RE may be defined as a subcarrier within a symbol, and multipleREs (e.g., 12 REs) can be defined as a resource block (RB). Thoughconcepts are generally described herein in terms of REs, the conceptscan be similarly applied to other divisions of time and frequencyresources (in other wireless communication systems) to achieve thedesired functions. In any case, as described, including multiple pilotswithin the signal can allow for improved phase noise suppression, whichmay allow for achieving higher modulation orders and increasedthroughput, etc.

In generating the waveform at Block 302, optionally at Block 304, themultiple pilots can be generated in different sets of REs that areinterleaved throughout the symbol. In an aspect, waveform generatingcomponent 252, e.g., in conjunction with processor(s) 212, memory 216,transceiver 202, communicating component 242, etc., can generate themultiple pilots in the different sets of REs that are interleaved (infrequency) throughout the symbol. For example, each set of REs caninclude contiguous REs, but the sets may be dispersed throughout REs ofthe symbol such that data REs can be between the sets. For example, thesymbol can include, in order of frequency, a set of REs for a firstpilot, followed by a set of REs for data, followed by a set of REs for asecond pilot, followed by a set of REs for data, and so on. In oneexample, the sets of REs for pilots can be of the same or substantiallysimilar length. In addition, for example, the sets of REs for data canbe of the same or substantially similar length. Moreover, in oneexample, each of the multiple pilots can correspond to one of the setsof data REs, and can be used to suppress phase noise for that set ofdata REs. An example is shown in FIG. 4 .

FIG. 4 illustrates an example of a waveform 400 having pilot REs 402,404 that are interleaved between data REs 406, and also data REs 408.Data can be mapped to the data REs 406, 408 with pilot REs interspersedbetween the data. This is one example of a waveform structure for havingmultiple pilots. In one example, having alternating pilot REs in thewaveform may be used where a receiver estimates and cancels phase noisein a frequency domain.

In generating the waveform at Block 302, optionally at Block 306, themultiple pilots can be generated in a single set of contiguous REs. Inan aspect, waveform generating component 252, e.g., in conjunction withprocessor(s) 212, memory 216, transceiver 202, communicating component242, etc., can generate the multiple pilots in the contiguous set of REsin the symbol. For example, For example, the symbol can include, inorder of frequency, a set of REs for the multiple pilots, followed by aset of REs for data. In another example, the set of REs for the multiplepilots may be at the end of the frequency resources for the symbol,somewhere in the middle of the REs, and/or the like. Moreover, in oneexample, each of the multiple pilots can correspond to a portion of REsin the data REs, and can be used to suppress phase noise for thatportion of data REs. An example is shown in FIG. 4 .

FIG. 4 illustrates an example of a waveform 410 having pilot REs 412 anddata REs 414. Data can be mapped to the data REs 414 and the pilot REs412 may be contiguous within the REs of the symbol. This is one exampleof a waveform structure for having multiple pilots. In one example,having the multiple pilots in a set of contiguous REs in the waveformmay be used where a receiver estimates and cancels phase noise in a timedomain.

In generating the waveform at Block 302, optionally at Block 308, themultiple pilots can be generated according to a sequence. In an aspect,waveform generating component 252, e.g., in conjunction withprocessor(s) 212, memory 216, transceiver 202, communicating component242, etc., can generate the multiple pilots according to the pilotsequence, which may facilitate improved detection and channel responseestimation. For example, the sequence may be a Zadoff-Chu sequence, a PNsequence (e.g., a pseudo-random binary sequence (PRBS)), which may begenerated by linear feedback shift registers, and/or substantially anysequence that can be used to generate an approximately white signal. Inan example, waveform generating component 252 can generate each of themultiple pilots to be of a pilot sequence, which may be the same ordifferent for each of the multiple pilots within a symbol, may vary forpilots as transmitted across multiple symbols, and/or the like.

In method 300, at Block 310, a signal having the waveform, including thedata and the multiple pilots, over the symbol can be transmitted. In anaspect, communicating component 242, e.g., in conjunction withprocessor(s) 212, memory 216, transceiver 202, etc., can transmit thesignal having the waveform, including the data and the multiple pilots,over the symbol. In one example, as described generating the waveform tohave multiple pilots may allow for higher order modulation, and thuscommunicating component 242 can modulate the signal based on the highermodulation order (e.g., 16K-QAM, 1M-QAM, etc.). In any case, a nodereceiving the signal can perform phase noise suppression based on themultiple pilots, which can allow for more effective noise suppression.

FIG. 5 illustrates a flow chart of an example of a method 500 forperforming frequency domain noise suppression of a waveform havingmultiple pilots. In an example, a base station 102/gNB 180, UE 104, orother node capable of wireless communications, can perform the functionsdescribed in method 500 using one or more of the components described inFIGS. 1-2 .

In method 500, at Block 502, a signal having a waveform that includesREs for data and separate REs for multiple pilots in a symbol can bereceived. In an aspect, communicating component 242, e.g., inconjunction with processor(s) 212, memory 216, transceiver 202, etc.,can receive (e.g., from another node) the signal having the waveformthat includes REs for data and separate REs for multiple pilots in thesymbol. As described, for example, the waveform may have pilot REs thatare interleaved with data REs throughout the waveform, or may otherwisehave pilot REs that are contiguous in a set of REs in the waveform.

In method 500, at Block 504, a channel response on the multiple pilotscan be estimated. In an aspect, noise suppressing component 254, e.g.,in conjunction with processor(s) 212, memory 216, transceiver 202,communicating component 242, etc., can estimate the channel response onthe multiple pilots. For example, noise suppressing component 254 mayknow the location of pilot REs within the waveform, which may be basedon a received configuration, implemented in instructions in memory 216(e.g., pursuant to a wireless communication technology standard orprotocol), etc. In one example, this may include noise suppressingcomponent 254 determining which of the pilots are dedicated to phasenoise cancellation, or receiving an external channel estimation (e.g.,from a demodulation reference signal received from the other node).Moreover, for example, noise suppressing component 254 can estimate thechannel response on each of the multiple pilots in turn, or as a totalchannel response over all of the pilots, etc.

In method 500, at Block 506, an equalization of the estimated channelresponse can be applied to cancel the channel response over the multiplepilots. In an aspect, noise suppressing component 254, e.g., inconjunction with processor(s) 212, memory 216, transceiver 202,communicating component 242, etc., can apply the equalization of theestimated channel response to cancel the channel response over themultiple pilots. For example, the equalization can be an average oranother representation of the channel response estimated on the multiplepilots.

In method 500, at Block 508, inter-carrier interference (ICI)coefficients can be determined. In an aspect, noise suppressingcomponent 254, e.g., in conjunction with processor(s) 212, memory 216,transceiver 202, communicating component 242, etc., can determine theICI coefficients, which may be based on the applying the channelestimation equalization to cancel the channel response over the pilots.For example, noise suppressing component 254 may determine the ICIcoefficients as an estimation of leakage coefficients from allsubcarriers to all subcarriers (carried out over the pilots), once thechannel response is cancelled over the pilots.

In method 500, at Block 510, phase noise from the signal can be removedby subtracting the ICI coefficients. In an aspect, noise suppressingcomponent 254, e.g., in conjunction with processor(s) 212, memory 216,transceiver 202, communicating component 242, etc., can remove (orsuppress) the phase noise from the signal by subtracting the ICIcoefficients. In one example, this can be performed using hard-decisionson the unknown data REs. For example, The ICI coefficients estimationcan be based not only on pilots but also on the data, or on harddecision on the data. A hard decision on the data can be a slicer unitwhich finds, from the quadrature amplitude modulation (QAM) map, theclosest symbol to the received symbol. Then these hard decision datasymbols can be used like the pilots to estimate the ICI coefficients.This process can be iteratively performed, e.g., in each iteration theICI coefficients can be estimated, then ICI correction can be applied,then improved hard decisions can be made on the data and again ICIcoefficients can be estimated with improved accuracy (e.g., using anumber of iterations). In addition, for example, this process ofsubtracting the ICI coefficients can be done iteratively, (e.g., feedthe input to this module, feed the output of the phase noise removedsignal as input into the function for estimating ICI coefficients todecrease the symbol-error rate in the hard-decision operation).

FIG. 6 illustrates a flow chart of an example of a method 600 forperforming time domain noise suppression of a waveform having multiplepilots. In an example, a base station 102/gNB 180, UE 104, or other nodecapable of wireless communications, can perform the functions describedin method 600 using one or more of the components described in FIGS. 1-2.

In method 600, at Block 602, a signal having a waveform that includesREs for data and separate REs for multiple pilots in a symbol can bereceived. In an aspect, communicating component 242, e.g., inconjunction with processor(s) 212, memory 216, transceiver 202, etc.,can receive (e.g., from another node) the signal having the waveformthat includes REs for data and separate REs for multiple pilots in thesymbol. As described, for example, the waveform may have pilot REs thatare interleaved with data REs throughout the waveform, or may otherwisehave pilot REs that are contiguous in a set of REs in the waveform.

In method 600, at Block 604, a passband filter can be applied to timedomain samples of the signal. In an aspect, noise suppressing component254, e.g., in conjunction with processor(s) 212, memory 216, transceiver202, communicating component 242, etc., can apply the passband filter tothe time domain samples of the signal. The passband can be the band ofthe pilots, such that the pilot portion of the samples is output.

In method 600, at Block 606, a channel response can be estimated on themultiple pilots. In an aspect, noise suppressing component 254, e.g., inconjunction with processor(s) 212, memory 216, transceiver 202,communicating component 242, etc., can estimate the channel response onthe multiple pilots that are output from the passband filter. Forexample, noise suppressing component 254 can estimate the channelresponse, h[n], in the time domain by applying cross-correlation betweenthe received samples r[n] and the reference pilots sequence p[n], e.g. aZadoff-Chu sequence, PN sequence, or another white sequence, asdescribed above.

In method 600, at Block 608, local maxima can be detected. In an aspect,noise suppressing component 254, e.g., in conjunction with processor(s)212, memory 216, transceiver 202, communicating component 242, etc., candetect local maxima in the estimated channel responses. For example,noise suppressing component 254 can extract the corresponding (index n0,value a0) as an estimation to the channel impulse response (CIR):h[n=n0]=a0.

In method 600, at Block 610, the received samples can be deconvolved. Inan aspect, noise suppressing component 254, e.g., in conjunction withprocessor(s) 212, memory 216, transceiver 202, communicating component242, etc., can deconvolve the received samples with the determined localmaxima. For example, noise suppressing component 254 can deconvolve thereceived samples r[n], with h[n] (e.g., where convolving with 1/H(z)) asthe equalization.

In method 600, at Block 612, the phase noise can be determined bydividing the samples by a sequence of the multiple pilots. In an aspect,noise suppressing component 254, e.g., in conjunction with processor(s)212, memory 216, transceiver 202, communicating component 242, etc., candetermine the phase noise by dividing the samples by the sequence of themultiple pilots. For example, dividing the samples by the referencesequence p[n], can yield the phase noise.

In method 600, at Block 614, the phase noise can be removed from thesignal. In an aspect, noise suppressing component 254, e.g., inconjunction with processor(s) 212, memory 216, transceiver 202,communicating component 242, etc., can remove (or suppress) the phasenoise from the signal by canceling the determined phase noise.

FIG. 7 is a block diagram of a MIMO communication system 700 including abase station 102 and a UE 104. The MIMO communication system 700 mayillustrate aspects of the wireless communication access network 100described with reference to FIG. 1 . The base station 102 may be anexample of aspects of the base station 102 described with reference toFIG. 1 . The base station 102 may be equipped with antennas 734 and 735,and the UE 104 may be equipped with antennas 752 and 753. In the MIMOcommunication system 700, the base station 102 may be able to send dataover multiple communication links at the same time. Each communicationlink may be called a “layer” and the “rank” of the communication linkmay indicate the number of layers used for communication. For example,in a 2×2 MIMO communication system where base station 102 transmits two“layers,” the rank of the communication link between the base station102 and the UE 104 is two.

At the base station 102, a transmit (Tx) processor 720 may receive datafrom a data source. The transmit processor 720 may process the data. Thetransmit processor 720 may also generate control symbols or referencesymbols. A transmit MIMO processor 730 may perform spatial processing(e.g., precoding) on data symbols, control symbols, or referencesymbols, if applicable, and may provide output symbol streams to thetransmit modulator/demodulators 732 and 733. Each modulator/demodulator732 through 733 may process a respective output symbol stream (e.g., forOFDM, etc.) to obtain an output sample stream. Eachmodulator/demodulator 732 through 733 may further process (e.g., convertto analog, amplify, filter, and upconvert) the output sample stream toobtain a DL signal. In one example, DL signals frommodulator/demodulators 732 and 733 may be transmitted via the antennas734 and 735, respectively.

The UE 104 may be an example of aspects of the UEs 104 described withreference to FIGS. 1-2 . At the UE 104, the UE antennas 752 and 753 mayreceive the DL signals from the base station 102 and may provide thereceived signals to the modulator/demodulators 754 and 755,respectively. Each modulator/demodulator 754 through 755 may condition(e.g., filter, amplify, downconvert, and digitize) a respective receivedsignal to obtain input samples. Each modulator/demodulator 754 through755 may further process the input samples (e.g., for OFDM, etc.) toobtain received symbols. A MIMO detector 756 may obtain received symbolsfrom the modulator/demodulators 754 and 755, perform MIMO detection onthe received symbols, if applicable, and provide detected symbols. Areceive (Rx) processor 758 may process (e.g., demodulate, deinterleave,and decode) the detected symbols, providing decoded data for the UE 104to a data output, and provide decoded control information to a processor780, or memory 782.

The processor 780 may in some cases execute stored instructions toinstantiate a communicating component 242 (see e.g., FIGS. 1 and 2 ).

On the uplink (UL), at the UE 104, a transmit processor 764 may receiveand process data from a data source. The transmit processor 764 may alsogenerate reference symbols for a reference signal. The symbols from thetransmit processor 764 may be precoded by a transmit MIMO processor 766if applicable, further processed by the modulator/demodulators 754 and755 (e.g., for SC-FDMA, etc.), and be transmitted to the base station102 in accordance with the communication parameters received from thebase station 102. At the base station 102, the UL signals from the UE104 may be received by the antennas 734 and 735, processed by themodulator/demodulators 732 and 733, detected by a MIMO detector 736 ifapplicable, and further processed by a receive processor 738. Thereceive processor 738 may provide decoded data to a data output and tothe processor 740 or memory 742.

The processor 740 may in some cases execute stored instructions toinstantiate a communicating component 242 (see e.g., FIGS. 1 and 2 ).

The components of the UE 104 may, individually or collectively, beimplemented with one or more application specific integrated circuits(ASICs) adapted to perform some or all of the applicable functions inhardware. Each of the noted modules may be a means for performing one ormore functions related to operation of the MIMO communication system700. Similarly, the components of the base station 102 may, individuallyor collectively, be implemented with one or more ASICs adapted toperform some or all of the applicable functions in hardware. Each of thenoted components may be a means for performing one or more functionsrelated to operation of the MIMO communication system 700.

The above detailed description set forth above in connection with theappended drawings describes examples and does not represent the onlyexamples that may be implemented or that are within the scope of theclaims. The term “example,” when used in this description, means“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, computer-executable code or instructionsstored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with aspecially programmed device, such as but not limited to a processor, adigital signal processor (DSP), an ASIC, a field programmable gate array(FPGA) or other programmable logic device, a discrete gate or transistorlogic, a discrete hardware component, or any combination thereofdesigned to perform the functions described herein. A speciallyprogrammed processor may be a microprocessor, but in the alternative,the processor may be any conventional processor, controller,microcontroller, or state machine. A specially programmed processor mayalso be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, multiple microprocessors, oneor more microprocessors in conjunction with a DSP core, or any othersuch configuration.

The functions described herein may be implemented in hardware, softwareexecuted by a processor, firmware, or any combination thereof. Ifimplemented in software executed by a processor, the functions may bestored on or transmitted over as one or more instructions or code on anon-transitory computer-readable medium. Other examples andimplementations are within the scope and spirit of the disclosure andappended claims. For example, due to the nature of software, functionsdescribed above can be implemented using software executed by aspecially programmed processor, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Also, as used herein, including in the claims, “or” as usedin a list of items prefaced by “at least one of” indicates a disjunctivelist such that, for example, a list of “at least one of A, B, or C”means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code means in the form of instructions or data structures andthat can be accessed by a general-purpose or special-purpose computer,or a general-purpose or special-purpose processor. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the common principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Furthermore, although elements of the describedaspects and/or embodiments may be described or claimed in the singular,the plural is contemplated unless limitation to the singular isexplicitly stated. Additionally, all or a portion of any aspect and/orembodiment may be utilized with all or a portion of any other aspectand/or embodiment, unless stated otherwise. Thus, the disclosure is notto be limited to the examples and designs described herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method for wireless communication at a userequipment (UE), comprising: receiving a signal having a waveformincluding, within a symbol, resource elements for a physical downlinkshared channel (PDSCH) and separate resource elements for multiplepilots, wherein each of the multiple pilots corresponds to and enablesphase tracking for a different data transmission portion of the PDSCHwithin the waveform; estimating, based on the multiple pilots, a channelresponse of the PDSCH; and removing, from the signal, a phase noisecomputed based on the channel response estimated for the PDSCH.
 2. Themethod of claim 1, wherein the waveform includes the multiple pilots indifferent sets of resource elements that are interleaved throughout thesymbol.
 3. The method of claim 2, wherein the multiple pilots eachinclude a same number of resource elements.
 4. The method of claim 1,wherein the waveform includes the multiple pilots in a first single setof contiguous resource elements separate from a second single set ofresource elements for the data.
 5. The method of claim 1, wherein thewaveform includes the multiple pilots according to a sequence.
 6. Themethod of claim 5, wherein the sequence is at least one of a Zadoff-Chusequence or a pseudo-noise (PN) sequence.
 7. The method of claim 1,further comprising applying a passband filter to time domain samples ofthe signal, wherein estimating the channel response of the PDSCH isbased on the time domain samples of the signal having the passbandfilter applied.
 8. An apparatus for wireless communication, comprising:one or more memories; and one or more processors coupled with the one ormore memories, wherein the one or more processors are configured to:receive a signal having a waveform including, within a symbol, resourceelements for a physical downlink shared channel (PDSCH) and separateresource elements for multiple pilots to, wherein each of the multiplepilots corresponds to and enables phase tracking for a different datatransmission portion of the PDSCH within the waveform; estimate, basedon the multiple pilots, a channel response of the PDSCH; and remove,from the signal, a phase noise computed based on the channel responseestimated for the PDSCH.
 9. The apparatus of claim 8, wherein thewaveform includes the multiple pilots in different sets of resourceelements that are interleaved throughout the symbol.
 10. The apparatusof claim 9, wherein the multiple pilots each include a same number ofresource elements.
 11. The apparatus of claim 8, wherein the waveformincludes the multiple pilots in a first single set of contiguousresource elements separate from a second single set of resource elementsfor the data.
 12. The apparatus of claim 8, wherein the waveformincludes the multiple pilots according to a sequence.
 13. The apparatusof claim 12, wherein the sequence is at least one of a Zadoff-Chusequence or a pseudo-noise (PN) sequence.
 14. The apparatus of claim 8,wherein the one or more processors are further configured to apply apassband filter to time domain samples of the signal, wherein the one ormore processors are configured to estimate the channel response of thePDSCH based on the time domain samples of the signal having the passbandfilter applied.
 15. An apparatus for wireless communication, comprising:means for receiving a signal having a waveform including, within asymbol, resource elements for a physical downlink shared channel (PDSCH)and separate resource elements for multiple pilots to, wherein each ofthe multiple pilots corresponds to and enables phase tracking for adifferent data transmission portion of the PDSCH within the waveform;means for estimating, based on the multiple pilots, a channel responseof the PDSCH; and means for removing, from the signal, a phase noisecomputed based on the channel response estimated for the PDSCH.
 16. Theapparatus of claim 15, wherein the waveform includes the multiple pilotsin different sets of resource elements that are interleaved throughoutthe symbol.
 17. The apparatus of claim 16, wherein the multiple pilotseach include a same number of resource elements.
 18. The apparatus ofclaim 15, wherein the waveform includes the multiple pilots in a firstsingle set of contiguous resource elements separate from a second singleset of resource elements for the data.
 19. The apparatus of claim 15,wherein the waveform includes the multiple pilots according to asequence.
 20. The apparatus of claim 19, wherein the sequence is atleast one of a Zadoff-Chu sequence or a pseudo-noise (PN) sequence. 21.A non-transitory computer-readable medium, comprising code executable byone or more processors for wireless communications, the code comprisingcode for: receiving a signal having a waveform including, within asymbol, resource elements for a physical downlink shared channel (PDSCH)and separate resource elements for multiple pilots to, wherein each ofthe multiple pilots corresponds to and enables phase tracking for adifferent data transmission portion of the PDSCH within the waveform;estimating, based on the multiple pilots, a channel response of thePDSCH; and removing, from the signal, a phase noise computed based onthe channel response estimated for the PDSCH.
 22. The non-transitorycomputer-readable medium of claim 21, wherein the waveform includes themultiple pilots in different sets of resource elements that areinterleaved throughout the symbol.
 23. The non-transitorycomputer-readable medium of claim 22, wherein the multiple pilots eachinclude a same number of resource elements.
 24. The non-transitorycomputer-readable medium of claim 21, wherein the waveform includes themultiple pilots in a first single set of contiguous resource elementsseparate from a second single set of resource elements for the data. 25.The non-transitory computer-readable medium of claim 21, wherein thewaveform includes the multiple pilots according to a sequence.
 26. Thenon-transitory computer-readable medium of claim 25, wherein thesequence is at least one of a Zadoff-Chu sequence or a pseudo-noise (PN)sequence.